Vue compatibility

[benjamincanac]

After many requests from the community (nuxt/ui#187, nuxt/ui#298, nuxt/ui#543, nuxt/ui#850, nuxt/ui#1514, etc.), the goal would be to make @nuxt/ui compatible for non-Nuxt apps as a Vite plugin I guess.

The minimal features would be to:

• Run Tailwind CSS vite plugin
• Inject components
• Inject composables
• Use @iconify/vue instead of @nuxt/icon (we don't need that much complexity I guess)
• Use VueUse https://vueuse.org/core/useDark/#usedark instead of @nuxtjs/color-mode
• Make Nuxt specific imports (#imports, #build, etc.) work
• Make Nuxt specific composables (useAppConfig, ~~useId~~, etc.) work
• Make theming with app.config.ts work in some way